Electrophotography is a dry photocopying technique that is widely used in imaging systems including laser printers. One step of the electrophotographic process is halftoning, in which a visual reproduction of an input digital image is printed using a reduced number of ink colors. Small dots of differing size and/or spacing, which are blended into smooth tones by the human eye, are used to convey the full range of colors. Thus, halftoning may be performed by rendering the reproduction of the input digital image through one or more screens of dots.
To reduce printing artifacts, screens of different frequencies (i.e., dot spacings) may be applied to different parts of the input digital image. For instance, symbol (e.g., text) and raster (e.g., image) objects in the input image may be rendered with high frequency screens, while vector (e.g., background) objects may be rendered with low frequency screens. This approach may be referred to as “object-oriented halftoning.”